The Pentagon plans to put at least 20 more US troops before military courts for abuse of detainees in the wake of last week's high profile trial of the ringleader in the Abu Ghraib scandal, military spokesmen said yesterday.

The various prosecutions of soldiers accused of mistreating and, in some cases, murdering detainees in Iraq, Afghanistan and Guantánamo Bay have been in the works for months, but have been largely overshadowed by the trial of the man who became known as the "primary torturer" of the notorious Baghdad prison.

Charles Graner, 36, was led away in leg irons at the weekend after being sentenced to 10 years for sexually humiliating and beating Iraqi detainees at Abu Ghraib.

But while the Pentagon had hoped that Graner's conviction would demonstrate its determination to impose harsh punishment on troops who abuse detainees, the verdict provoked two very different reactions yesterday.

Although there was no official response from Iraq's interim government, reaction on the streets of Baghdad was condemnatory. Abdul-Razak Abdul-Fattah, a 65-year-old retired army officer, said he was shocked to see television footage of Graner leaving the court smiling and laughing even though his legs and hands were shackled.

"It showed on his face that he did not regret the shameful acts he and his colleagues committed," he said.

Meanwhile, informal polls by newspapers on US army bases found troops believed low-ranking troops such as Graner have been singled out for exemplary punishment, while senior officers - who knew of the abuse for months - have gone free.

"The truth is my son was convicted the day President Bush went on television and said seven bad apples disgraced the country," his mother, Irma Graner, told reporters.

Such misgivings are unlikely to be allayed by the coming line-up at Fort Hood base in Texas, the primary US venue for such trials.

So far, only one of the accused troops is known to be an officer. The rest are enlisted personnel, fuelling criticism that the Pentagon is reluctant to pursue allegations of torture and abuse further up the chain of command.

Since the start of the war in Iraq, 26 members of the US army have been referred to trial for abuse or murder of detainees; 18 trials are still pending, said Lieutenant Colonel Barry Venables.

However, far more - 75 troops - have been subjected to other disciplinary measures, and have not been brought to trial.

Separately, the navy is preparing to prosecute three more service personnel, and has subjected seven others to disciplinary measures.

It was unclear yesterday whether further members of the Marine Corps are to face military courts. So far, 14 marines have been convicted of abuse in military courts.

Nine other marines remain under investigation for various forms of abuse, including murder.

A new set of trials for US soldiers accused in the abuse of detainees gets under way next Friday when Sergeant Shane Werst faces pre-trial hearings on murder charges. Sgt Werst, 31, a combat engineer who was decorated for service in Kosovo and South Korea, is accused in the killing of an Iraqi in Balad more than a year ago. The Iraqi, Naser Ismail, died in custody following his arrest on January 3 last year.

Sgt Werst is also accused of forcing other soldiers to lie about the death. His hearing next week will determine whether there is evidence for a court martial.

Naser's was one of two unauthorised killing of Iraqis that day. Last week, Sgt Tracy Perkins was sentenced to six months for forcing two Iraqis to jump from a bridge into the Tigris near Samarra. One of the men drowned.

Lieutenant Jack Saville, accused in the same episode, goes on trial on March 15. His commanding officer, Lieutenant-Colonel Nathan Sassaman was disciplined, but not subjected to a trial, for ordering a cover-up of the death.

Other soldiers involved in the Abu Ghraib scandal are due to go before military courts. Sergeant Javal Davis, accused of forcing Iraqis to form a naked human pyramid, is scheduled for court martial on February 2. Specialist Sabrina Harman, who is accused of taking the now infamous picture of the human pyramid, is scheduled for trial on March 30.

The final trial involves Private Lynndie England, who had a son with Graner last year, and who was photographed pointing at the genitals of naked Iraqis. No trial date has yet been set for her.